The present invention relates to an ink supply system in an ink jet system printer.
In general, in an ink jet system printer, ink droplets from a nozzle are issued toward a recording paper, and then desired ink droplets are deflected in a desired direction when they pass through an appropriate deflection means. The deflected ink droplets are deposited on the recording paper in order to record desired symbols corresponding to printing information supplied. Especially, in an ink jet system printer of the charge amplitude controlled type wherein an ink stream from a nozzle having an ultrasonic vibrator is broken into ink droplets at a given vibration frequency, and the individual ink droplets, being charged by a charging electrode in accordance with printing information, are deflected in accordance with the amplitude of charges carried thereon as they pass through an electrostatic field of a fixed high voltage thereby printing desired symbols such as alphabet characters, it is of importance that the application of charging signals is accurately timed to be in agreement with the droplet separation phase. Therefore, it is necessary to hold the predetermined phase relationship between the droplet separation and the ultrasonic vibration substantially constant.
The ink liquid used in the ink jet system printer as set forth above undergoes changes in physical constants such as the viscosity and surface tension thereof in a fashion dependent upon the ink liquid temperature. Therefore, it is necessary to maintain the ink liquid at a predetermined temperature in order to ensure stable printing.
It has been proposd to provide an ink liquid warmer in the ink supply system in order to hold the ink liquid at a predetermined temperature, and to maintain the viscosity and surface tension of the ink liquid at a predetermined value. The conventional ink liquid warmer as shown in our copending application Ser. No. 509,549 filed on Sept. 26, 1974 "INK LIQUID WARMER FOR INK JET SYSTEM PRINTER" now U.S. Pat. No. 4,007,684, issued Feb. 15, 1977, was not satisfactory in its response velocity.